Steroidal estrogens represent a very important group of biologically active agents which find wide use in both medicine and in veterinary practice where they are employed for a variety of conditions including treatment of hypogonadal women, inhibition of ovulation in women, when they are generally admixed with a progestogen, hormonal support of menopausal and post-menopausal women including treatment of osteoporosis, treatment of acne in men and women, slowing down male pattern baldness in men and women, treatment of atrophic vaginitis, treatment of breast cancer in post-menopausal women and in men, treatment of benign prostatic hypertrophy and prostatic carcinoma in men, chemical caponization of chickens and promoting growth of cattle. In recent years it has become apparent, however, that estrogenic products presently in use possess certain undesirable side effects which must be set against the undoubted benefits resulting from their use. For example, diethylstilbestrol, a once widely used and well established estrogen has been implicated as possibly being responsible for vaginal cancer and adenosis in the female offspring of pregnant women treated with the compound (Lancet 1975, 1960). Also, ethinyl estradiol and mestranol, which represent estrogenic components in current oral contraceptives, are now known to be involved in certain serious side effects associated with oral contraceptives including depression (Nature 243, 58 (1973)), hypertension (Am. J. Obstet. Gynecol. 112, 912 (1972)), carbohydrate and lipid abnormalities (Lancet 1969, October 11, p. 783), interference with blood clotting mechanism resulting in thrombosis and stroke (Ann. Intern. Med. 72, 111 (1970)), and jundice (Am. J. Obstet. Gynecol. 119, 165 (1974)). The use of the above mentioned estrogens or of estradiol, estrone or the sulphated conjugates of estrogens by menopausal and post-menopausal women is often attended by undesirable uterine bleeding and spotting. Also, the administration of estrogens to post-menopausal women has been implicated as a cause of endometrial cancer occurring in such women (Science 191, 838 (1976)). Topical estrogens are used for the treatment of aging skin in women and are known to produce uterine bleeding and spotting at effective dose levels. The use of estrogens for the treatment of acne in women can lead to uterine bleeding and spotting and breast tenderness, and in men, gynecomastia and impotence. The use of estrogens in the treatment of benign prostatic hypertrophy and of prostatic carcinoma in men is known to be associated with a high incidence of fatal thrombosis, gynecomastia and impotence which significantly negates the valuable therapeutic effects of the medication. Consequently there is a need for an improved method of inducing an estrogenic effect in humans and domestic animals in need thereof which will be substantially free of the undesirable side effects associated with estrogen therapy.